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Localization of the Epileptogenic Zone by Ictal and Interictal SPECT with 99m Tc‐Ethyl Cysteinate Dimer in Patients with Medically Refractory Epilepsy
Author(s) -
Oliveira Andréa J.,
Costa Jaderson C.,
Hilário Lisiane N.,
Anselmi O. Estrela,
Palmini André
Publication year - 1999
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/j.1528-1157.1999.tb00765.x
Subject(s) - ictal , epilepsy , ictal interictal spect analysis by spm , refractory (planetary science) , medicine , neuroscience , psychology , psychiatry , physics , astrobiology
Summary:Purpose: To evaluate the accuracy, feasibility and clinical value of both ictal and interictal 99m Tc‐ethyl cysteinate dimer (ECD) single photon emission computed tomography (SPECT) in patients with medically refractory epilepsy. Methods: The study included 75 consecutive patients, 48 with temporal lobe epilepsy (TLE group), and 27 with extra‐temporal epilepsy (ExT group). The accuracy of SPECT was analyzed considering the final diagnosis reached by convergence of clinical, electrophysiologic, structural, pathologic and outcome data. Results: Ictal SPECT correctly identified the epileptogenic zone in 21 (91.3%) of 23 patients, whereas interictal SPECTs could correctly identify the epileptogenic zone in only 41 (62.1%) of 66 patients (χ 2 = 5.56, df = 1, p < 0.05). Results were similar when the two study groups were analyzed separately. Moreover, ictal studies had significantly higher specificity (91.3 vs. 60.6%) and positive predictive value (91.3 vs. 66.2%) than interictal studies for the whole series of patients. Considering all tools used in the preoperative workup of these patients, ictal SPECT significantly contributed to the final topographic diagnosis in seven of 14 patients from TLE group and in six of nine patients from the ExT group. In these patients, ictal SPECT either obviated the need for invasive EEG or helped to define where to concentrate the efforts of invasive investigation. Conclusions: These data demonstrate that ictal SPECT can be easily achieved by using 99m Tc‐ECD and can accurately localize the epileptogenic zone in both temporal and extratemporal epilepsies. Ictal ECD SPECT proved to be significantly more sensitive and specific than interictal ECD SPECT, and clinically useful in the definition of the epileptogenic zone.